For example, a conventional pulverized coal fired boiler has a furnace that is formed in a hollow shape and installed in an up-and-down direction, and a plurality of combustion burners are arranged in a furnace wall along a circumferential direction, the combustion burners being arranged in a multiple-stage manner in the vertical direction. The combustion burner supplies thereto a fuel-air mixture of pulverized coal (fuel) in which coal is pulverized and primary air (air) and, at the same time, supplies thereto hot combustion air, wherein the fuel-air mixture and the hot combustion air are blown into the furnace to form flames thus combusting the fuel-air mixture in the furnace. Furthermore, the furnace has a flue gas duct connected with the upper portion thereof, the flue gas duct is provided with a superheater, a reheater, a fuel economizer, and the like that are used for recovering the heat of flue gas, and heat exchange is performed between the flue gas and water that are generated by combusting the fuel-air mixture in the furnace thus generating steam.
Here, in the combustion burner of the pulverized coal fired boiler, the fuel is composed of a solid material and hence, the fuel is brought into contact with a member arranged in an area through which the fuel circulates. Consequently, there exists the possibility of generating abrasion in a passage of the fuel, or the like. In this regard, Patent Literature 1 discloses a straightening vane arranged in the inside or the passage, the straightening vane being formed of a high-chrome steel material, or configured to apply thereto the lining of a hard material, such as ceramics or cermet.